In “A Sound of Thunder,” the short story by Ray Bradbury, the main character travels back in time to hunt dinosaurs. He crushes a butterfly underfoot in the prehistoric jungle, and when he returns to the present, the world he knows is changed: the feel of the air, a sign in an office, the election of a U.S. president. The butterfly was “a small thing that could upset balances and knock down a line of small dominoes and then big dominoes and then gigantic dominoes, all down the years across Time.”
This “butterfly effect” that Bradbury illustrated — where a small change in the past can result in enormous future effects — is not reserved for fiction. As the famed mathematician and meteorologist Edward Lorenz discovered by accident, natural systems do exist in which tiny shifts in initial conditions can lead to highly variable outcomes. These systems, including weather and even how fluids mix — are known as chaotic. Chaotic systems are normally understood within the realm of classical physics, which is the method we use to predict how objects will move to a certain degree of accuracy (think motion, force or momentum from your high school science class.)
